Fifty years ago, Martin Luther King Jr. declared his desire for a more colorblind America in his stirring “I have a dream” speech.

“I have a dream that my four children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character,” he said in one of his most memorable lines.

But five decades after the March on Washington, just a bare majority of Americans – and fewer than one-in-five African Americans – believe that dream has been realized.

What’s more, the percentage of Americans who think race relations in the country are good has declined considerably since President Barack Obama – the nation’s first black president – took office in 2009.

According to an NBC News/Wall Street Journal poll released last month, 54 percent of respondents agreed with the statement that America is a nation where people are judged by their character, not their skin color. Forty-five percent disagreed, including a whopping 79 percent of African Americans.

In the same poll, another bare majority – 52 percent – said race relations in the U.S. are good, which was down from 79 percent who said this in Jan. 2009, 72 percent who said it in 2010 and 71 percent who said it in 2011.

One possible explanation for this drop: The poll was released soon after a jury found George Zimmerman, who is of white and Hispanic descent, not guilty of second-degree murder in the shooting death of Trayvon Martin, who was black. Zimmerman said he shot Martin, who was unarmed, in self-defense and his lawyers have said race played no role.

A rodeo clown at the Missouri state fair donning an Obama mask as the ringleader taunted him;

A federal judge ruling that New York City’s controversial stop-and-frisk policy by city policemen is unconstitutional and amounts to “indirect racial profiling;”

And most recently, three Oklahoma teens being charged in the shooting death of an Australian baseball player.

“There is no doubt that race has been – and continues to be – the most important issue that divides us,” Lonnie Bunch, the director of the Smithsonian’s National Museum of African American History and Culture, said Tuesday on MSNBC’s “Daily Rundown.” “We're always going to be grappling about questions about race.”

“We have a lot of work to do. The dream is not yet fulfilled,” Rep. John Lewis, D-Ga., added on NBC’s “Meet the Press.”

Of course, it’s undeniable that the state of race relations in this country has improved since King’s speech in 1963. Think of the Civil Rights Act. The Voting Rights Act. The election of the nation’s first black president.

As Obama himself said in his July comments, “Each successive generation seems to be making progress in changing attitudes when it comes to race. It doesn’t mean we’re in a post-racial society. It doesn’t mean that racism is eliminated. But when I talk to [daughters] Malia and Sasha, and I listen to their friends and I seem them interact, they’re better than we are – they’re better than we were – on these issues. And that’s true in every community that I’ve visited all across the country.”

In his “I have a dream” speech 50 years ago, Martin Luther King Jr. also spoke of progress – and the continual need for it.